1. Technical Field
The present invention relates to a semiconductor device and a semiconductor device manufacturing method.
2. Related Art
Conventionally, a vertical MOSFET (Metal-Oxide-Semiconductor Field-Effect-Transistor) is known that includes a trench gate, as shown in Non-Patent Document 1, for example. In order to mitigate the electric field concentration at the bottom portion of the trench gate, a source trench having a p-type region is provided at a position deeper than the bottom portion of the gate trench, as shown in Non-Patent Document 2, for example. Furthermore, ion injection is performed on the bottom portion and the side walls of the gate trench provided in the p-type base region to form an n-type region, as shown in Patent Document 1, for example.